A new poll shows Turkish Prime Minister Recep Tayyip Erdogan’s governing party is trailing in advance of next year’s elections.

The Sonar Arastirma survey, which has a margin of error of plus-or-minus 2 percentage points, shows Mr. Erdogan’s Justice and Development Party (AKP) at 31.1 percent and the Republican People's Party (CHP) at 33.5 percent.

The numbers are virtually unchanged since Sonar Arastirma’s last poll, taken in May, before nine Turkish nationals were killed in a melee with Israeli commandos aboard a flotilla trying to break the Gaza blockade.

Mr. Erdogan, whose government already had seen cooling relations with Israel, stoked popular wrath and threatened to sever ties with his country’s longtime ally unless it apologized for the incident.

But any “flotilla bump” appears to have vanished.

“There is a sense among some elements of the population that AKP has overreached on foreign policy,” said Turkey expert Steven Cook, a senior fellow for Middle Eastern studies at the Council on Foreign Relations.

“I am not talking about the kind of die-hard nationalist secularists, but that important ‘middle’ or ‘center’ who aren’t Islamists or militant nationalist secularists,” Mr. Cook said. “These people voted for AKP in 2002 because of Turkey’s economic free fall and again in 2007 because of Turkey’s economic progress. They liked the EU reforms of 2003 and 2004.

“They aren’t all that unhappy with the general thrust of Turkish foreign policy, but they are starting to ask questions about AKP’s foreign policy activism.”

Last month, Turkey was one of only two U.N. Security Council members to vote against a new round of sanctions on Iran for its illicit nuclear activities. In April, it held a military drill with Syria. Relations with Israel, meanwhile, remain at a breaking point.

The Turkish economy grew at an average of 6 percent over the AKP’s first five years in power and is expected to grow at 3.5 percent this year, despite the global economic slowdown. However, it is still wrestling with an unemployment rate around 13 percent.

CHP has seen a revival under the new leadership of Kemal Kilicdaroglu.

But Mr. Cook cautioned that Erdogan-wary Westerners should not invest too much hope in polls nearly a year before notoriously late-breaking Turkish elections, even if their numbers pan out.

“People should keep in mind that CHP is no panacea,” he said. “Over the better part of the last decade, it has been perniciously anti-American, anti-EU, anti-Israel, and anti-globalization.”